1. Field
A separator and a rechargeable lithium battery including the separator are disclosed.
2. Description of the Related Art
A conventional non-aqueous rechargeable lithium battery includes a separator made of a porous insulating film and interposed between positive and negative electrodes, and the pores of the film are impregnated by an electrolyte solution including a lithium salt dissolved therein. Such a non-aqueous rechargeable lithium battery has suitable (e.g., excellent) high-capacity and high energy density characteristics.
However, when the positive and negative electrodes therein are repetitively shrunk and expanded during the charge and discharge cycles and thus, react with the separator or the electrolyte solution and the non-aqueous rechargeable lithium battery may be easily deteriorated, have internal and external short circuits, and become hot rapidly. When the battery becomes hot rapidly as described above, the separator may become molten and may rapidly shrink or be destroyed and thus, the rechargeable battery may be short-circuited again.
In order to reduce or prevent this problem, a comparable (conventional) separator is widely formed of a porous polyethylene film having a suitable (e.g., an excellent) shutdown characteristic, being easily handled, and low in cost. Herein, the term “shutdown” refers to an event when a separator is partly fused and thus, its pores are closed and a current is cut off, when a battery is heated up due to overcharge, external or internal short circuit, or the like. In addition, an attempt has been made to improve the safety of the non-aqueous rechargeable lithium battery by improving the heat resistance of an electrode material and a material for the separator and the like, and in particular, to ensure (secure) safety even when the separator therein is sharply shrunk or destroyed.